Debugging debugging information using dynamic call trees

Debugging tools rely on compiler-generated metadata to present a source-language view, but current compilers often throw away or corrupt debugging information in optimised programs.Attempts to test debugging information are confounded by ad-hoc limitations of the debug info formats and a lack of clarity on whether the compiler or the format is to blame for any given loss.Adopting the "residual program" conceptual view of debug info, we conduct a study of the quality of debugging information in respect of the source-level dynamic call trees it can recover.We compare the trees recovered from optimised and unoptimised versions of the same program, producing a classification of the observed divergences.For each class, we analyse whether format or compiler is to blame and identify specific ways to address these defects.We also validate our classification across a larger collection of well-known codebases.